## CMT62

##
Strong-Coupling Theory of Superconductivity

**Author(s):** D. Rainer and J. A. Sauls

**Comments:** 34 pages

**Publication:**

Chapter in `*Superconductivity: From Basis Principles to the Latest Developments*', pp. 45-78,
Lecture Notes of the ICTP Spring College in Condensed Matter on ``Superconductivity''
ICTP, Trieste, Italy, 27 April - 19 June 1992,
Eds. L. N. Butcher and Yu Lu,
World Scientific, Singapore, 1995 [ISBN: 978-981-4590-22-8].
[DOI]
**Abstract:**

The electronic properties of correlated metals with a strong electron-phonon coupling may be
understood in terms of a combination of Landau's Fermi-liquid theory and the strong-coupling
theory of Migdal and Eliashberg. In these lecture notes we discuss the
microscopic foundations of this phenomenological Fermi-liquid model of
correlated, strong-coupling metals. We formulate the basic equations of
the model, which are quasiclassical transport equations that describe both
equilibrium and non-equilibrium phenomena for the normal and superconducting
states of a metal. Our emphasis is on superconductors close to equilibrium,
for which we derive the general linear response theory. As an application
we calculate the dynamical conductivity of strong-coupling superconductors.